Summer officially arrived across the Northern Hemisphere on Friday, June 20, 2025, as the summer solstice marked the longest day of the year and the start of astronomical summer. From Connecticut to Chicago and beyond, people welcomed the peak sunshine with a mix of outdoor celebrations and, in some places, sweltering heat warnings.
The summer solstice, which occurred at 10:42 p.m. Eastern Time according to the National Weather Service, is the moment when the Earth's axial tilt is at its maximum toward the sun. This tilt causes the sun to travel its longest and highest arc across the sky, resulting in the most daylight hours of the year for those north of the equator. In Connecticut, for example, residents experienced over 15 hours of sunlight on Friday, while Chicago basked in 15 hours and 14 minutes of sunshine, coinciding with extreme heat advisories and "feels-like" temperatures soaring above 100 degrees Fahrenheit for three consecutive days.
The term "solstice" comes from the Latin words "sol," meaning sun, and "stitium," meaning pause or stop, reflecting the sun's apparent halt at its highest point in the sky before it begins its gradual retreat. This celestial event has been observed and celebrated by civilizations for millennia, with monuments like Stonehenge precisely aligned to the sun’s path during solstices. These ancient traditions continue today, with communities across Connecticut hosting various summer solstice events such as yoga sessions in Stamford, sunset sails on the Connecticut River in Essex, and Midsummer markets and gatherings stretching into the following week.
While the solstice marks the longest day, it does not signal the hottest time of the year. According to The Old Farmer’s Almanac, the land and oceans remain relatively cool after spring, causing a seasonal temperature lag. This means the peak heat typically arrives later in summer, often in late July or August. The Almanac forecasts that June temperatures will be near normal in most regions, but July and August are expected to bring above-average warmth, with states like Texas, Oklahoma, Kansas, and Iowa potentially experiencing temperatures up to 4°F above normal. The Deep South and Desert Southwest are also predicted to face significantly warmer conditions.
From an astronomical perspective, summer begins precisely at the solstice, but meteorologists define seasons differently. Meteorological summer started on June 1 and lasts through August 31, dividing the year into fixed three-month periods based on temperature cycles. This distinction helps weather services and climatologists analyze seasonal trends more effectively.
The solstice is part of a broader dance between Earth’s orbit and axial tilt. As our planet orbits the sun on a tilted axis, sunlight distribution varies throughout the year, creating seasons. When the Northern Hemisphere tilts toward the sun, it experiences longer days and shorter nights, culminating in the summer solstice. Conversely, the Southern Hemisphere simultaneously experiences its shortest day and the onset of winter.
Equinoxes provide a contrast to solstices. These occur when Earth's axis and orbit align such that both hemispheres receive nearly equal sunlight, resulting in roughly equal day and night lengths. The Northern Hemisphere’s vernal (spring) equinox falls between March 19 and 21, while the autumnal equinox occurs between September 21 and 24. At the equator, the sun is directly overhead at noon during equinoxes, and uniquely, both the North and South Poles are illuminated by sunlight at the same time.
For many, the unofficial start of summer is celebrated earlier, around Memorial Day weekend, which in 2025 fell on Monday, May 26. This holiday traditionally marks the beginning of outdoor festivities and warmer weather for much of the United States. The summer of 2025 also offers a treat for those who enjoy long weekends, with three three-day weekends: Memorial Day, Independence Day on Friday, July 4, and Labor Day on Monday, September 2. This trio will continue through 2026 and 2027, providing ample opportunities for summer fun and relaxation.
As the days begin to shorten following the solstice, the Northern Hemisphere moves steadily toward autumn. The official end of summer arrives with the autumnal equinox on Sunday, September 22, 2025, when day and night are approximately equal in length, signaling the transition to fall’s cooler temperatures and changing foliage.
Across the country, residents are encouraged to enjoy the season’s longest daylight hours responsibly, especially amid heat advisories. Whether it’s picking strawberries, attending a bonfire, joining community dances, or simply soaking in the sun at beaches, lakes, and parks, the summer solstice remains a powerful reminder of Earth’s rhythms and humanity’s enduring connection to the natural world.
